March 4, 2025
Keio University
A research group from the Graduate School of Pharmaceutical Sciences at Keio University, led by Yuki Otani (a third-year student in the Doctoral Programs), Associate Professor Shunsuke Kimura, and Professor Koji Hase, has discovered that specialized cells called "M cells," located in the tear duct (lacrimal passage) that connects the eyes and nose, are involved in the exacerbation of allergic conjunctivitis.
The eyes are exposed to foreign substances such as pollen and dust, and tears are produced to wash them away. Within the "tear duct" through which these tears pass, there is an immune watchtower called tear duct-associated lymphoid tissue (TALT). The research group has previously shown that M cells exist on the surface of TALT and take in foreign substances flowing into the tear duct. In this study, the group generated genetically modified mice lacking M cells in their TALT. They found that the absence of M cells reduced the uptake of foreign substances into the TALT, dulling the immune surveillance function against these substances. On the other hand, when allergic conjunctivitis was induced in the M-cell-deficient mice, the symptoms of conjunctivitis were alleviated. The number of cells producing IgE antibodies, which cause allergic reactions, was also reduced. These results revealed that M cells take in allergy-inducing substances in the tear duct and are also involved in promoting allergic reactions in the TALT. This suggests the possibility that regulating the function of M cells could suppress the onset of allergies. The results of this research were published in the online edition of the international academic journal "Mucosal Immunology" on February 1, 2025.
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